RE: BVM Mig 15 build
My upper rudder is operational and has a hidden linkage. Pull-pull with an 8411 using welding rod (3/16" diameter) for the torque rod into the bottom of the rudder. Works very well. I used 3/16" diameter welding rod (brass bushed) for the torque rod between the upper and lower rudder as well.
If you conceal the elevator linkages this is done with 5/32" welding rod I believe. Dave Ribbe has them on his. I did not conceal my elevator linkages.